{"history":[],"article":{"id":"7592c9c5-e4f7-42d1-acb0-c5c0d70b1e0c","title":"Submillimetre astronomy","slug":"submillimetre-astronomy","content":":::summary\n:::\n\n# \n**Submillimetre astronomy** or **submillimeter astronomy** (see [spelling differences](https://bliptext.com/articles/spelling-differences)) is the branch of [observational astronomy](https://bliptext.com/articles/observational-astronomy) that is conducted at submillimetre wavelengths (i.e., [terahertz radiation](https://bliptext.com/articles/terahertz-radiation)) of the [electromagnetic spectrum](https://bliptext.com/articles/electromagnetic-spectrum).\nAstronomers place the sub[millimetre](https://bliptext.com/articles/millimetre) waveband between the [far-infrared](https://bliptext.com/articles/far-infrared) and [microwave](https://bliptext.com/articles/microwave) wavebands, typically taken to be between a few hundred [micrometres](https://bliptext.com/articles/micrometre) and a [millimetre](https://bliptext.com/articles/millimetre).\nIt is still common in submillimetre astronomy to quote wavelengths in 'microns', the old name for micrometre.\nUsing submillimetre observations, astronomers examine [molecular clouds](https://bliptext.com/articles/molecular-cloud) and [dark cloud](https://bliptext.com/articles/dark-nebula) cores with a goal of clarifying the process of [star formation](https://bliptext.com/articles/star-formation) from earliest [collapse](https://bliptext.com/articles/gravitational-collapse) to [stellar birth](https://bliptext.com/articles/stellar-birthline).\nSubmillimetre observations of these dark clouds can be used to determine [chemical abundances](https://bliptext.com/articles/astrochemistry) and [cooling mechanisms](https://bliptext.com/articles/interstellar-medium) for the [molecules which comprise them](https://bliptext.com/articles/list-of-interstellar-and-circumstellar-molecules).\nIn addition, submillimetre observations give information on the mechanisms for the [formation and evolution of galaxies](https://bliptext.com/articles/galaxy-formation-and-evolution).\n# [The Caltech Submillimeter Observatory at Mauna Kea Observatory was commissioned in 1988, and has a 10.4 m (34 ft) dish | upload.wikimedia.org/wikipedia/commons/b/b5/Caltech-Submillimeter-Observatory///%28straightened%29.jpg]\n\n# From the ground\nThe most significant limitations to the detection of astronomical emission at submillimetre wavelengths with ground-based observatories are atmospheric emission, noise and attenuation.\nLike the [infrared](https://bliptext.com/articles/infrared-astronomy), the submillimetre atmosphere is dominated by numerous [water vapour](https://bliptext.com/articles/water-vapour) [absorption bands](https://bliptext.com/articles/absorption-bands) and it is only through \"windows\" between these bands that observations are possible.\nThe ideal submillimetre observing site is dry, cool, has stable weather conditions and is away from urban population centres.\nOnly a handful of sites have been identified.\nThey include [Mauna Kea](https://bliptext.com/articles/mauna-kea-observatory) ([Hawaii](https://bliptext.com/articles/hawaii), United States), the [Llano de Chajnantor Observatory](https://bliptext.com/articles/llano-de-chajnantor-observatory) on the Atacama Plateau ([Chile](https://bliptext.com/articles/chile)), the [South Pole](https://bliptext.com/articles/south-pole), and Hanle in India (the Himalayan site of the [Indian Astronomical Observatory](https://bliptext.com/articles/indian-astronomical-observatory)).\nComparisons show that all four sites are excellent for submillimetre astronomy, and of these sites Mauna Kea is the most established and arguably the most accessible.\nThere has been some recent interest in high-altitude Arctic sites, particularly [Summit Station](https://bliptext.com/articles/summit-camp) in Greenland where the PWV ([precipitable water](https://bliptext.com/articles/precipitable-water) vapor) measure is always better than at Mauna Kea (however Mauna Kea's equatorial latitude of 19 degrees means it can observe more of the southern skies than Greenland).\nThe [Llano de Chajnantor Observatory](https://bliptext.com/articles/llano-de-chajnantor-observatory) site hosts the [Atacama Pathfinder Experiment](https://bliptext.com/articles/atacama-pathfinder-experiment) (APEX), the largest submillimetre telescope operating in the southern hemisphere,\nand the world's largest ground based astronomy project, the [Atacama Large Millimeter Array](https://bliptext.com/articles/atacama-large-millimeter-array) (ALMA), an [interferometer](https://bliptext.com/articles/astronomical-radio-interferometry) for submillimetre wavelength observations made of 54 12-metre and 12 7-metre radio telescopes.\nThe [Submillimeter Array](https://bliptext.com/articles/submillimeter-array) (SMA) is another interferometer, located at Mauna Kea, consisting of eight 6-metre diameter radio telescopes.\nThe largest existing submillimetre telescope, the [James Clerk Maxwell Telescope](https://bliptext.com/articles/james-clerk-maxwell-telescope), is also located on Mauna Kea.\n# [Panoramic view of the Chajnantor plateau, spanning about 180 degrees from north (on the left) to south (on the right) shows the antennas of the Atacama Large Millimeter Array. | upload.wikimedia.org/wikipedia/commons/5/5c/ALMA%E2%80%99s///World///At///Night.jpg]\n\n# From the stratosphere\nWith [high-altitude balloons](https://bliptext.com/articles/high-altitude-balloon) and aircraft, one can get above more of the atmosphere.\nThe [BLAST](https://bliptext.com/articles/blast-telescope) experiment and [SOFIA](https://bliptext.com/articles/sofia) are two examples, respectively, although [SOFIA](https://bliptext.com/articles/sofia) can also handle near infrared observations.\n\n# From orbit\nSpace-based observations at the submillimetre wavelengths remove the ground-based limitations of atmospheric absorption.\nThe first submillimeter telescope in space was the Soviet BST-1M, located in the scientific equipment compartment of the [Salyut-6 orbital station](https://bliptext.com/articles/salyut-6).\nIt was equipped with a mirror with a diameter of 1.5 m and was intended for astrophysical research in the ultraviolet (0.2 - 0.36 microns), infrared (60 - 130 microns) and submillimeter (300 - 1000 microns) spectral regions, which are of interest to those who are interested in which makes it possible to study [molecular clouds](https://bliptext.com/articles/molecular-cloud) in space, as well as obtain information about the processes taking place in the upper layers of the [Earth's atmosphere](https://bliptext.com/articles/atmosphere-of-earth).\nThe [Submillimeter Wave Astronomy Satellite](https://bliptext.com/articles/submillimeter-wave-astronomy-satellite) (SWAS) was launched into low Earth orbit on December 5, 1998 as one of [NASA](https://bliptext.com/articles/nasa)'s Small Explorer Program (SMEX) missions.\nThe mission of the spacecraft is to make targeted observations of giant molecular clouds and dark cloud cores.\nThe focus of SWAS is five spectral lines: [water](https://bliptext.com/articles/water) (H₂O), isotopic [water](https://bliptext.com/articles/water) (H₂¹⁸O), isotopic [carbon monoxide](https://bliptext.com/articles/[carbon](https://bliptext.com/articles/carbon)-monoxide) (¹³CO), molecular [oxygen](https://bliptext.com/articles/oxygen) (O₂), and neutral [carbon](https://bliptext.com/articles/carbon) (C I).\nThe SWAS satellite was repurposed in June, 2005 to provide support for the NASA [Deep Impact](https://bliptext.com/articles/deep-impact-spacecraft) mission.\nSWAS provided water production data on the comet until the end of August 2005.\nThe [European Space Agency](https://bliptext.com/articles/european-space-agency) launched a space-based mission known as the [Herschel Space Observatory](https://bliptext.com/articles/herschel-space-observatory) (formerly called Far Infrared and Sub-millimetre Telescope or FIRST) in 2009.\nHerschel deployed the largest mirror ever launched into space (until December 2021, with the launch of the near-infrared [James Webb Space Telescope](https://bliptext.com/articles/james-webb-space-telescope)) and studied radiation in the far infrared and submillimetre wavebands.\nRather than an Earth orbit, Herschel entered into a [Lissajous orbit](https://bliptext.com/articles/lissajous-orbit) around, the second [Lagrangian point](https://bliptext.com/articles/lagrangian-point) of the Earth-Sun system.\nis located approximately 1.5 million km from Earth and the placement of Herschel there lessened the interference by infrared and visible radiation from the Earth and Sun.\nHerschel's mission focused primarily on the origins of galaxies and galactic formation.","current_revision":null,"created_by":"kACnuQmH5k9Nr5VNVEpVeg7XpvUmMctD","created_at":"2025-01-25T21:43:28.231Z","updated_at":"2025-01-25T21:43:28.231Z","search_vector":"'astronomi':2 'submillimetr':1","search_content":" \n \n\n# \n**Submillimetre astronomy** or **submillimeter astronomy** (see [spelling differences](https://bliptext.com/articles/spelling-differences)) is the branch of [observational astronomy](https://bliptext.com/articles/observational-astronomy) that is conducted at submillimetre wavelengths (i.e., [terahertz radiation](https://bliptext.com/articles/terahertz-radiation)) of the [electromagnetic spectrum](https://bliptext.com/articles/electromagnetic-spectrum).\nAstronomers place the sub[millimetre](https://bliptext.com/articles/millimetre) waveband between the [far-infrared](https://bliptext.com/articles/far-infrared) and [microwave](https://bliptext.com/articles/microwave) wavebands, typically taken to be between a few hundred [micrometres](https://bliptext.com/articles/micrometre) and a [millimetre](https://bliptext.com/articles/millimetre).\nIt is still common in submillimetre astronomy to quote wavelengths in 'microns', the old name for micrometre.\nUsing submillimetre observations, astronomers examine [molecular clouds](https://bliptext.com/articles/molecular-cloud) and [dark cloud](https://bliptext.com/articles/dark-nebula) cores with a goal of clarifying the process of [star formation](https://bliptext.com/articles/star-formation) from earliest [collapse](https://bliptext.com/articles/gravitational-collapse) to [stellar birth](https://bliptext.com/articles/stellar-birthline).\nSubmillimetre observations of these dark clouds can be used to determine [chemical abundances](https://bliptext.com/articles/astrochemistry) and [cooling mechanisms](https://bliptext.com/articles/interstellar-medium) for the [molecules which comprise them](https://bliptext.com/articles/list-of-interstellar-and-circumstellar-molecules).\nIn addition, submillimetre observations give information on the mechanisms for the [formation and evolution of galaxies](https://bliptext.com/articles/galaxy-formation-and-evolution).\n# [The Caltech Submillimeter Observatory at Mauna Kea Observatory was commissioned in 1988, and has a 10.4 m (34 ft) dish | upload.wikimedia.org/wikipedia/commons/b/b5/Caltech-Submillimeter-Observatory///%28straightened%29.jpg]\n\n# From the ground\nThe most significant limitations to the detection of astronomical emission at submillimetre wavelengths with ground-based observatories are atmospheric emission, noise and attenuation.\nLike the [infrared](https://bliptext.com/articles/infrared-astronomy), the submillimetre atmosphere is dominated by numerous [water vapour](https://bliptext.com/articles/water-vapour) [absorption bands](https://bliptext.com/articles/absorption-bands) and it is only through \"windows\" between these bands that observations are possible.\nThe ideal submillimetre observing site is dry, cool, has stable weather conditions and is away from urban population centres.\nOnly a handful of sites have been identified.\nThey include [Mauna Kea](https://bliptext.com/articles/mauna-kea-observatory) ([Hawaii](https://bliptext.com/articles/hawaii), United States), the [Llano de Chajnantor Observatory](https://bliptext.com/articles/llano-de-chajnantor-observatory) on the Atacama Plateau ([Chile](https://bliptext.com/articles/chile)), the [South Pole](https://bliptext.com/articles/south-pole), and Hanle in India (the Himalayan site of the [Indian Astronomical Observatory](https://bliptext.com/articles/indian-astronomical-observatory)).\nComparisons show that all four sites are excellent for submillimetre astronomy, and of these sites Mauna Kea is the most established and arguably the most accessible.\nThere has been some recent interest in high-altitude Arctic sites, particularly [Summit Station](https://bliptext.com/articles/summit-camp) in Greenland where the PWV ([precipitable water](https://bliptext.com/articles/precipitable-water) vapor) measure is always better than at Mauna Kea (however Mauna Kea's equatorial latitude of 19 degrees means it can observe more of the southern skies than Greenland).\nThe [Llano de Chajnantor Observatory](https://bliptext.com/articles/llano-de-chajnantor-observatory) site hosts the [Atacama Pathfinder Experiment](https://bliptext.com/articles/atacama-pathfinder-experiment) (APEX), the largest submillimetre telescope operating in the southern hemisphere,\nand the world's largest ground based astronomy project, the [Atacama Large Millimeter Array](https://bliptext.com/articles/atacama-large-millimeter-array) (ALMA), an [interferometer](https://bliptext.com/articles/astronomical-radio-interferometry) for submillimetre wavelength observations made of 54 12-metre and 12 7-metre radio telescopes.\nThe [Submillimeter Array](https://bliptext.com/articles/submillimeter-array) (SMA) is another interferometer, located at Mauna Kea, consisting of eight 6-metre diameter radio telescopes.\nThe largest existing submillimetre telescope, the [James Clerk Maxwell Telescope](https://bliptext.com/articles/james-clerk-maxwell-telescope), is also located on Mauna Kea.\n# [Panoramic view of the Chajnantor plateau, spanning about 180 degrees from north (on the left) to south (on the right) shows the antennas of the Atacama Large Millimeter Array. | upload.wikimedia.org/wikipedia/commons/5/5c/ALMA%E2%80%99s///World///At///Night.jpg]\n\n# From the stratosphere\nWith [high-altitude balloons](https://bliptext.com/articles/high-altitude-balloon) and aircraft, one can get above more of the atmosphere.\nThe [BLAST](https://bliptext.com/articles/blast-telescope) experiment and [SOFIA](https://bliptext.com/articles/sofia) are two examples, respectively, although [SOFIA](https://bliptext.com/articles/sofia) can also handle near infrared observations.\n\n# From orbit\nSpace-based observations at the submillimetre wavelengths remove the ground-based limitations of atmospheric absorption.\nThe first submillimeter telescope in space was the Soviet BST-1M, located in the scientific equipment compartment of the [Salyut-6 orbital station](https://bliptext.com/articles/salyut-6).\nIt was equipped with a mirror with a diameter of 1.5 m and was intended for astrophysical research in the ultraviolet (0.2 - 0.36 microns), infrared (60 - 130 microns) and submillimeter (300 - 1000 microns) spectral regions, which are of interest to those who are interested in which makes it possible to study [molecular clouds](https://bliptext.com/articles/molecular-cloud) in space, as well as obtain information about the processes taking place in the upper layers of the [Earth's atmosphere](https://bliptext.com/articles/atmosphere-of-earth).\nThe [Submillimeter Wave Astronomy Satellite](https://bliptext.com/articles/submillimeter-wave-astronomy-satellite) (SWAS) was launched into low Earth orbit on December 5, 1998 as one of [NASA](https://bliptext.com/articles/nasa)'s Small Explorer Program (SMEX) missions.\nThe mission of the spacecraft is to make targeted observations of giant molecular clouds and dark cloud cores.\nThe focus of SWAS is five spectral lines: [water](https://bliptext.com/articles/water) (H 2 O), isotopic [water](https://bliptext.com/articles/water) (H 2 18 O), isotopic [[carbon](https://bliptext.com/articles/carbon) monoxide](https://bliptext.com/articles/[carbon](https://bliptext.com/articles/carbon)-monoxide) ( 13 CO), molecular [oxygen](https://bliptext.com/articles/oxygen) (O 2 ), and neutral [carbon](https://bliptext.com/articles/carbon) (C I).\nThe SWAS satellite was repurposed in June, 2005 to provide support for the NASA [Deep Impact](https://bliptext.com/articles/deep-impact-spacecraft) mission.\nSWAS provided water production data on the comet until the end of August 2005.\nThe [European Space Agency](https://bliptext.com/articles/european-space-agency) launched a space-based mission known as the [Herschel Space Observatory](https://bliptext.com/articles/herschel-space-observatory) (formerly called Far Infrared and Sub-millimetre Telescope or FIRST) in 2009.\nHerschel deployed the largest mirror ever launched into space (until December 2021, with the launch of the near-infrared [James Webb Space Telescope](https://bliptext.com/articles/james-webb-space-telescope)) and studied radiation in the far infrared and submillimetre wavebands.\nRather than an Earth orbit, Herschel entered into a [Lissajous orbit](https://bliptext.com/articles/lissajous-orbit) around, the second [Lagrangian point](https://bliptext.com/articles/lagrangian-point) of the Earth-Sun system.\nis located approximately 1.5 million km from Earth and the placement of Herschel there lessened the interference by infrared and visible radiation from the Earth and Sun.\nHerschel's mission focused primarily on the origins of galaxies and galactic formation.","revisionCount":0},"hasMore":false,"nextCursor":null}

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